1. Field of the Invention
The invention relates to fitted bed sheets and methods of forming such sheets.
2. Description of the Prior Art
Conventional fitted sheets or "contour" sheets having elastic or shirring at the corners have been in widespread use for years to serve as the bottom sheet overlying standard mattresses. Because of the well-known problem of flat sheets loosening when used as the bottom sheet on hospital beds, particularly when the bed is articulated, conventional three-dimensional type fitted sheets have been used to some extent in hospitals. However, for a number of reasons such conventional fitted sheets are unsuitable for hospital and other institutional uses. Among these reasons is the high cost of such fitted sheets. Further, the elastic at the corners tends to break down in the laundering and ironing process. These conventional sheets are also difficult to handle in typical flat-ironer machines. To eliminate ironing, the fitted sheets have been manufactured with blends of natural and synthetic fibers so that they may be conditioned and dried in tumblers or they may be air-dried. However, this requires the use of particular types of fibers and increases the expense.
Furthermore, conventional fitted sheets cannot be handled by automatic folding machines. Because of the sheets' three-dimensional (or "developed") shape, any folding process (hand or automatic) results in an uneven, space-consuming volume that does not lend itself to neat stacking. Yet another disadvantage of conventional fitted sheets is that the bed making operation requires considerable physical effort because a relatively heavy and inflexible mattress must be fitted at the corners or ends to get the sheet in place.
Therefore, there is an acute need for a fitted sheet that will overcome these disadvantages, especially for hospital and other institutional uses.